http://msdn.microsoft.com/en-us/library/bb314749(AX.10).aspx
Temporary Tables vs. Containers
Microsoft Dynamics AX supports a special data type called a container. This data type can be used just as you would use a temporary table. For more information, see Containers.
Data in containers are stored and retrieved sequentially, but a temporary table enables you to define indexes to speed up data retrieval. Containers provide slower data access if you are working with many records. However, if you are working with only a few records, use a container.
Another important difference between temporary tables and containers is how they are used in method calls. When you pass a temporary table into a method call, it is passed by reference. Containers are passed by value. When a variable is passed by reference, only a pointer to the object is passed into the method. When a variable is passed by value, a new copy of the variable is passed into the method. If the computer has a limited amount of memory, it might start swapping memory to disk, slowing down application execution. When you pass a variable into a method, a temporary table may provide better performance than a container.
Using temporary tables as the primary data source in EP page posse a number of technical limitations. The most significant being the lack of context.
Context is not maintained on temporary tables hence the web part that contains it cannot be used as a provider to other webparts like the toolbar webpart which is connected to the current context of the provider view. The flow of activities in the process is hindered since additional processing needs to be done to pass the context explicitly to the caller. Temporary tables cannot be used as the source of a lookup control either.
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